Household food insecurity has substantial detrimental effects on children, but little is known about the mechanisms through which these effects occur. This study investigated some possible mechanisms by examining associations of food insecurity reported by children and mothers with daily activities, school absenteeism, and stunting. We conducted a cross-sectional study in a nonprobabilistic sample of 131 mother-child pairs from a poor peri-urban area in Miranda State, Venezuela. We assessed food insecurity in children by using an instrument developed through a naturalistic approach that had 10 items for food insecurity and 9 items for management strategies. To obtain mothers' reports of food insecurity, a previously validated 12-item instrument was used. Children's daily activities, school absenteeism, and stunting were measured. Chi-square tests for contingency tables and logistic and multiple regression analyses were used to test associations of food insecurity with outcomes. There was no association between mothers' reports of food-insecurity and any child outcome. Children's reports of food insecurity were associated with higher odds of doing passive home chores (OR: 1.17; 95% CI: 1.02, 1.32), cooking at home (OR: 1.21; 95% CI: 1.05, 1,38), taking care of siblings (OR: 1.15; 95% CI: 1.01, 1.31), and doing labor (OR: 1.22; 95% CI: 1.04, 1.42) and lower odds of playing video games (OR: 0.86; 95% CI: 0.76, 0.98) (all P < 0.03). Children's reports of management strategies were associated with 5 of 7 work activities measured. Labor in food-insecure children was the main activity that explained school absenteeism. Food insecurity reported by children can be assessed by pediatricians, school personnel, and other practitioners by using a simple instrument to identify food-insecure children and to respond to mitigate their food insecurity and its consequences.